What is your current gas mileage (do not use the VIC for this)?
If it is horrible then it could very well be the upstream O2 sensor.
Change the spark plugs, air filter, Cap, rotor, and spark wires every 30,000 miles.
Gas filter is your call. I replace mine at 30k miles but it can probably go to 60,000 miles since gas is delivered very clean today and the gas tank is plastic.
94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new
88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new